These are Rectify Series drop-in speaker for Bowser C-628/630/636 & M360/636 locomotives. The speakers use carpet-tape or a strap of tape to mount and no modifications are needed to replace the factory speaker(s).
 
Three rear-mount speakers are available depending on the chassis you have. The traditional chassis used two 35mm speakers and will accommodate the long Scale Sound Systems BOWS-C600 speaker. At numerous points in time (unknown) the chassis has received various weights added. The UFIT-7940 fits perfectly on some models while the UFIT-7935 is required on others. It should also be possible to remove these small weights, held on by two screws, and use the longer BOWS-C600 speaker. I have only had the double-35 chassis in my shop and have only heard stories and seen some photos of the other versions. You MUST remove your shell and see what chassis you have. Then you can decide which speaker system to use. The larger the speaker used, the deeper your sound will be.
 
You can choose to add a front-mounted speaker for better horn/bell localization using the UFIT-9318-RC1, which sits on the shelf behind the cab (at least on the double-35 chassis).
 
The speakers come fully assembled and tested.
 
Dimensions are:
BOWS-C600-RC1: 9mmH x 17mmW x 70mmL
UFIT-7940-RC1: 9mmH x 17mmW x 40mmL
UFIT-7935-RC1: 9mmH x 17mmW x 35mmL
 
VIDEO: https://youtu.be/VmWetWNwYoI